288 THE PRINCIPLES OF Part II. 



An excellent case for investigation is afforded by the 

 Deer Family. In all the species, excepting one, the 

 horns are developed in the male alone, though certainly 

 transmitted through the female, and capable of occasional 

 abnormal development in her. In the reindeer, on the 

 other hand, the female is provided with horns ; so that 

 in this species, the horns ought, according to our rule, 

 to appear early in life, long before the two sexes had 

 arrived at maturity and had come to differ much in 

 constitution. In all the other species of deer the horns 

 ought to appear later in life, leading to their develop- 

 ment in that sex alone, in which they first appeared 

 in the progenitor of the whole Family. Now in seven 

 species, belonging to distinct sections of the family and 

 inhabiting different regions, in which the stags alone 

 bear horns, I find that the horns first appear at periods 

 varying from nine months after birth in the roebuck to 

 ten or twelve or even more months in the stags of the 

 six other larger species. 24 But with the reindeer the 

 case is widely different, for as I hear from Prof. Nilsson, 

 who kindly made special enquiries for me in Lapland, 

 the horns appear in the young animals within four or 

 five weeks after birth, and at the same time in both 

 sexes. So that here we have a structure, developed at 

 a most unusually early age in one species of the family, 

 and common to both sexes in this one species. 



In several kinds of antelopes the males alone are 



24 I am much obliged to Mr. Cupples for having made enquiries for 

 me in regard to the Roebuck and Red Deer of Scotland from Mr. 

 Robertson, the experienced head-forester to the Marquis of Breadalbane. 

 In regard to Fallow-deer, I am obliged to Mr. Eyton and others for 

 information. For the Cervus dices of N. America, see ' Land and Water,' 

 1868, p. 221 and 254; and for the C. Yirginianus and strongyloceros of 

 the same continent, see J. D. Caton, in ' Ottawa Acad, of Nat. So.' 

 1868, p. 13. For Cervus Eldi of Pegu, see Lieut. Beavan, ' Proc. 

 Zoolog. Soc' 1867, p. 762. 



